The "World's Greatest Retirement Portfolio" Continues to Outperform

It's been almost 23 months since I introduced the World's Greatest Retirement Portfolio to Foolish readers. This was, has been, and will continue to be my way of helping the world to invest better. Putting my money where my mouth is, I pledged to put at least $4,000 behind each stock and attempt to hold each one for at least three years -- though I've already broken that promise.

Since I began, the market has returned 24.1%, which is pretty darn good by historical measures. Though this portfolio has been outperforming the market by double digits for well over a year now, it is currently ahead by just 3.3 percentage points.

Read below to see why the margin between the two is narrowing, and at the end, I'll offer up access to a special premium report on one of these 10 companies.

Source: Fool.com. All numbers accurate as of market close March 31, 2013. *Returns are for position in ATVI held from July 15, 2011, to Sept. 9, 2012, and transferred over to BIDU on Sept. 15, 2012.

One company that can't catch a breakMore or less, the companies in this portfolio didn't perform terribly during the month of March, they just weren't able to keep pace with the S&P 500, which climbed over 3% during the month. That wasn't the case, however, for Intuitive Surgical , maker of the da Vinci surgical robot.

I've covered the stock's dive already, but there are three simple events that caused the stock to drop. First, the Journal of the American Medical Association questioned the need for robotic hysterectomies. Second, the FDA announced it was investigating a rise in the company's incidents reports. Finally, the president of the American Congress of Obstetricians and Gynecologists publicly echoed the concerns raised in the JAMA article.

Three companies having a good monthEven though the portfolio as a whole isn't leading the market by quite as much, three stocks had a relatively good March.

Shares of Latin American club wholesaler PriceSmart were up 5%. This came on the heels of the announcement that the company's net sales increased 7.8% during the month of February, which included an impressive 8.9% increase in same-store sales. PriceSmart also announced it has acquired land in Tegucigalpa, Honduras, to open up its third store in the country.

The total return from my investments in Coca-Cola and Johnson & Johnson also increased markedly during March. Part of this was due to the fact that Coke issued its quarterly dividend during the month -- which is one of the reasons I invested in the company.

Johnson & Johnson's stock, on the other hand, was able to sidestep an FDA denial for its blood-thinner, Xarelto, to set all-time highs during March. That's what you can expect from a company as diverse in its health care offerings as Johnson & Johnson. It also probably didn't hurt when the company received approval for Invokana, its type 2 diabetes drug.

Is it time to worry about Intuitive?Though I've made clear my intention to sit on my shares of Intuitive Surgical, recently, some investors have questioned the company's future. However, Intuitive Surgical expert Karl Thiel believes a visible path to long-term growth persists. Will Intuitive capitalize, or be crushed by unforeseen pitfalls? His report highlights all of the key opportunities and risks facing the company -- and includes a full year of ongoing updates as key new hits -- so be sure to claim your copy by clicking here now.